This invention relates generally to transmission interlock devices, and particularly to poppet interlocks and pins coacting in a system of parallel shift rods.
Numerous prior art transmission interlock mechanisms have been proposed and tried with varying degrees of success. A major problem, however, is related to the complexity and expense of prior art apparatus utilized in achieving poppet interlock and positive stop functions. Both of these functions are inherently related to shift rail movement; the interlock function involving devices permitting movement of only one rail at a time, the positive stop function relating to permissible movement range of a given rail. The two concepts have not heretofore been combined in one simple mechanism, however, and each has been typically associated with bulky, cumbersome apparatus. For example, one prior art poppet interlock system requires two springs for each individual interlock, while prior art mechanisms designed to provide positive stop functions have traditionally utilized machine spacers in conjunction with transmission housing bosses or fork hubs.
Another problem of prior art interlock mechanisms has been related to an occasional overextension of the pins extending through shift rods. Such an event causes a transmission to become jammed, resulting in incapacitation of an associated vehicle.